The present invention relates to a sampling device comprising a sampling container for reception of a sample volume and a connecting piece adapted to be connected to a fitting mounted on a vessel or pipe of a processing installation or the like, the connecting piece having a sample passage which is provided with a stationary valve part and a corresponding valve member which is displaceable between a closed position, in which it abuts the stationary valve part and closes the sample passage, and an open position, in which the sample passage is open.
EP 0141 940 corresponding to U.S. Pat. No. 4,580,452 discloses a sampling container being connected through a pipe to a manually operated sampling valve which may be screwed into a fitting mounted on a conduit forming part of a chemical plant installation. The fitting is also provided with a manually operated valve in order to close the outlet from the conduit when the sampling valve is not connected to the fitting. To take a sample, firstly the sampling valve must be screwed into the fitting, the two valves must be opened and subsequently closed, and the sampling valve must be disconnected from the fitting. Obviously, this procedure is time-consuming, and furthermore there is a risk of forgetting to close one of the valves after having taken a sample, whereby possibly hazardous product could escape from the sampling system. Additionally, the configuration of the sampling container and its connected valve is awkward to handle and susceptible to damages if dropped, which may result in product spillage. Furthermore, the device is suitable for the sampling of fluids only, as products such as powder or granules would clog up the passages through the valves and the pipe.
DE 40 34 700 describes a dual-valve system for the taking of a fluid sample from a pipe system. A first valve member in the form of a truncated cone is arranged in a pipe rotatably about an axis perpendicular to the direction of flow in the pipe and has a through passage in-line with the pipe opening when set to its open position. In this open position, a sample may be taken from the pipe through a second valve arranged in a connection piece inserted in the lower side of the truncated cone. After having taken a sample, both valves are closed, and the internal product-contaminated surfaces which are situated between the two closed valves are cleaned by means of a spray device. However, this procedure is most cumbersome and time-consuming. Furthermore, the system also has the disadvantage that the second valve must be closed manually in order to prevent spillage of the product sampled. The sampling container protrudes radially from the second valve and makes the device awkward in use.
DS 43 01 174 discloses a sampling valve having a semi-cylindrical valve member arranged rotatably in a bore extending tangentially to the inner surface of a pipe wall. An external sampling container is screwed into a fitting which is mounted on the outside of the pipe wall and is in fluid connection with the bore through a passage. When the valve member is in its open position, a fluid may pass from the pipe to the sampling container. After removing the sampling container from the fitting, the container is open to the surroundings and consequently product may be spilled.
DE 197 35 586 shows a sampling valve having an outlet opening through the wall of a pipe and a corresponding valve member which by means of a spindle is manually operable from the outside of the pipe. A sampling container for the reception of a fluid may be held under the outlet opening when the valve is opened.